A driving support apparatus mounted in a vehicle which is configured to alert a driver of the vehicle when there is a possibility that an object crosses an expected route of the vehicle has been conventionally known (Hereinafter, a vehicle in which the driving support apparatus is mounted may be also referred to as an “own vehicle”.). This kind of driving support apparatus estimates the expected route of the own vehicle in front of the own vehicle based on a traveling direction of the own vehicle. Then, the driving support apparatus is configured to determine that there is a possibility that an object crosses the expected route of the own vehicle when it is estimated that the object intersects this expected route within a predetermined time, or the object exists in a virtual region set on and around this expected route within a predetermined time, or the like, and to alert the driver of the own vehicle. Therefore, it is important to properly estimate an expected route of the own vehicle in order to properly alert the driver of the own vehicle.
For example, an apparatus disclosed in Japanese Patent Application Laid-Open (kokai) No. 2016-6440 (hereinafter, referred to as a “prior art apparatus”) determines whether or not the own vehicle is in a state where the own vehicle is actually turning left or right (hereinafter, may be also simply referred to as a “turning-right-or-left-state”) at a place where the turning is allowed (hereinafter, may be simply referred to as a “turning place”). Further, the prior art apparatus estimates a curved expected route along an actual traveling route of the own vehicle when the own vehicle is determined to be in the turning-right-or-left-state, and sets the aforementioned virtual region (This region is referred to as a “target region” in Japanese Patent Application Laid-Open (kokai) No. 2016-6440.) based on the expected route.
It should be noted that in the present specification, “a vehicle turns left” means a series of actions that the vehicle tries to start turning left and thereafter actually turns left to finish turning left, and “a vehicle turns right” means a series of actions that the vehicle tries to start turning right and thereafter actually turns right to finish turning right.
More specifically, the prior art apparatus comprises a direction indicator sensor for detecting an operating state of a direction indicator, a GPS (Global Positioning System) sensor for detecting a current position of the own vehicle, and a memory in which a map information including a position and a shape of the turning place and the like is stored. In this map information, a point referred to as an “exit point” is registered in advance at an exit of each turning place.
The prior art apparatus determines that the own vehicle is in the turning-right-or-left-state when the direction indicator sensor has detected that the direction indicator is in the operating state. When the prior art apparatus determines that the own vehicle is in the turning-right-or-left-state, the prior art apparatus determines whether or not the own vehicle is positioned at the turning place based on the current position of the own vehicle acquired from the GPS sensor and the map information stored in the memory. Thereafter, when the prior art apparatus determines that the own vehicle is positioned at the turning place, the prior art apparatus estimates all possible routes from the current position of the own vehicle to the aforementioned exit point as estimated routes, and sets these estimated routes and their surroundings as the virtual region. Therefore, it is disclosed in Japanese Patent Application Laid-Open (kokas) No. 2016-6440 that the prior art apparatus can properly alert the driver of the own vehicle.